This purpose of this core is to provide for centralized pathology review of all tissues obtained from the individual projects. This core laboratory will perform immuno-histochemistry studies for tumors analyzed within the projects, and undertake assays to determine methylation silencing of a DNA repair gene (MGMT), and functional assays of DNA mismatch repair in tumor tissues. Dr. Ashley Hill is a board certified Anatomic Pathologist and Director of Anatomic Pathology at St. Jude Children's Research Hospital.